Upgrading from CE to EE Premium to restore deleted project

We use a “self-managed” GitLab CE v12.10.14 instance. We do not have any outside (i.e. internet) connectivity to our GitLab server.

Last week a developer accidently deleted a project that was being used solely for issue tracking. Our IT department had turned off whatever automated back-up system they were using for our GitLab instance over a year ago.

After reading that versions of GitLab EE Premium v12.6-13.1 contained the feature “delayed project deletion”, the hope was that because the version of our installed GitLab CE instance (12.10.14) was between v12.6-13.1 that it might have this “delayed project deletion” feature (turned off?) and that the deleted project isn’t really gone but somewhere on disk and that if we upgraded to GitLab EE Premium v12.6-13.1 we might be able to recover it. Is this possible?